Metastasis from renal cell carcinoma to thyroid presenting as rapidly growing neck mass

Renal cell carcinoma (RCC) is commonly known as the “internist’s tumor” because of itsunpredictable behavior. Metastasis to the thyroid gland is rarely found in clinical practice.PRESENTATION OF CASE: We report a rare case of non-thyroid malignancies NTM from renal cell carcinoma1.5 years after radical nephrectomy in a 58-year-old man with a rapidly growing neck mass.DISCUSSION: Malignant melanoma, breast carcinoma, lung, and skin cancer are the most common sourcesof non-thyroid malignancies (NTM). Although metastases of NTMs to the thyroid gland are uncommon inclinical practice, it should be considered in patients with a history of prior malignancy and a new thyroidmass.CONCLUSION: Isolated thyroid metastasis should be considered in patients with a previous history ofcancer and newly developing thyroid mass